% Ca-Oscil-Astrocyte.ode
% Ref: Laventovich and Hemkin, A mathematical model of spontaneous calcium(II)  oscillations 
% in astrocytes.  J Theor Biol 2008; 251(4):553-60.

% Units: microM/sec; microM; sec
% x: cytosolic Ca; y: Ca concencentration in ER; z: IP3 concentration

init x=0.1, y=1.5, z=0.1

parm vm2=15, vm3=40, vin=0.05, vp=0.05, k2=0.1
parm kcaa=0.15, kcat=0.15, kip3=0.1, kp=0.3
parm kdeg=0.08, kout=0.5, kf=0.5, n=2.02, m=2.2

vserca=vm2*(x^2/(x^2+k2^2))
vplc=vp*(x^2/(x^2+kp^2))
vcicr=4*vm3*((kcaa^n)*(x^n)/((x^n+kcaa^n)*(x^n+kcat^n)))*(z^m/(z^m+kip3^m))*(y-x)

dx/dt=vin-kout*x+vcicr-vserca+kf*(y-x)
dy/dt=vserca-vcicr-kf*(y-x)
dz/dt=vplc-kdeg*z

@ meth=Euler, dt=0.01, total=600
@ yp=x, ylo=0, yhi=0.7, xlo=0, xhi=600, bound=10000

done